Finding the Fourth Proportional to 21,981.88, 30,335.04 and 12,905.49

Step by Step Solution

1. Step 1: Write the proportion equation
   21,981.88 : 30,335.04 = 12,905.49 : x
2. Step 2: Convert to fraction form
   21,981.88/30,335.04 = 12,905.49/x
3. Step 3: Cross multiply
   21,981.88x = 30,335.04 × 12,905.49
4. Step 4: Simplify right side
   21,981.88x = 391,488,669.13
5. Step 5: Solve for x
   x = 391,488,669.13/21,981.88
6. Step 6: Final answer
   x = 17,809.61